Kong API Gateway Interview Questions [2025]

Kong API Gateway Interview Questions

1. What is Kong API Gateway, and what are its core components?

Kong API Gateway is an open-source, scalable platform for managing APIs and microservices, offering routing, authentication, rate limiting, and observability. Its core components include the Proxy for traffic routing, Admin API for configuration, plugins for extensibility, Kong Manager for UI management, and Kong Mesh for service mesh integration. It supports DB and DB-less modes, with enterprise features like Vitals for analytics and RBAC for access control, making it ideal for DevOps-driven API ecosystems.

Learn more about OpenShift administration for containerized API management.

2. How does Kong's DB-less mode function?

DB-less mode uses YAML or JSON configurations stored in memory or files, eliminating database dependencies for faster scaling and simplified deployments. It supports GitOps workflows by storing configs in version control, enabling CI/CD automation with tools like Jenkins or ArgoCD. This mode is ideal for Kubernetes environments, offering real-time updates without downtime.

3. What is Kong Mesh, and how does it enhance API management?

Kong Mesh is an enterprise service mesh built on Envoy, extending Kong Gateway with Layer 7 traffic management for microservices. It supports mTLS for secure communication, traffic splitting for canary releases, and observability with metrics and traces, integrating seamlessly with DevOps pipelines for automated service discovery and security.

4. Why use Kong plugins, and how do they work?

Kong plugins extend functionality for authentication, rate limiting, logging, and more, applied globally, per service, or per route. They execute in a chain during request/response cycles, allowing custom logic like JWT validation or CORS handling. Plugins are configurable via Admin API, supporting DevOps automation for dynamic updates.

5. How does Kong integrate with Kubernetes?

Kong integrates with Kubernetes via the Kong Ingress Controller, managing APIs as Ingress resources. It supports CRDs for custom routing and plugins, DB-less mode for declarative configs, and Kong Mesh for service mesh. This enables DevOps teams to automate scaling, monitoring, and security in Kubernetes clusters.

6. What is Kong Manager, and its role in enterprise?

Kong Manager is the enterprise UI for managing services, routes, plugins, and consumers. It provides RBAC, real-time analytics via Vitals, and API documentation, simplifying administration for DevOps teams without CLI dependency, while ensuring secure, scalable API governance.

7. How does Kong's rate limiting plugin work?

Kong's rate limiting plugin uses token bucket or leaky bucket algorithms to control API request rates, preventing abuse. It supports distributed limiting with Redis for scalability and integrates with CI/CD for automated threshold updates, ensuring high availability in production environments.

8. What is Kong's Admin API, and its use cases?

Kong's Admin API provides programmatic control over configurations, enabling automation of services, routes, plugins, and consumers. Use cases include CI/CD integration for deploying configs, real-time monitoring, and bulk updates. It supports scoped API keys for secure DevOps operations.

Explore how Red Hat OpenShift integrates with API gateways.

9. Why is Kong suitable for microservices?

Kong's lightweight proxy, plugin ecosystem, and service mesh capabilities via Kong Mesh make it ideal for microservices. It supports dynamic routing, mTLS for security, and observability with Prometheus, enabling DevOps teams to manage complex, distributed architectures efficiently.

10. When to use Kong's hybrid mode?

• Combining DB and DB-less for flexibility.
• During gradual migration to DB-less.
• For real-time config syncing in mixed setups.
• In DevOps for automated hybrid deployments.
• Ensuring compliance with hybrid policies.
• Scaling across diverse environments.
• Monitoring hybrid performance metrics.

11. What is Kong's Vitals plugin?

Vitals is an enterprise plugin for real-time observability, collecting metrics on API latency, error rates, and throughput. It integrates with Prometheus and Grafana for dashboards, enabling DevOps teams to monitor SLOs and troubleshoot performance issues in production.

12. How does Kong's mTLS plugin enhance security?

The mTLS plugin enforces mutual TLS authentication for service-to-service communication, validating client and server certificates. It integrates with DevOps pipelines for automated certificate management and ensures compliance with security standards in microservices environments.

13. What are Kong's authentication plugins?

Kong supports authentication plugins like key-auth for API keys, oauth2 for OAuth 2.0, jwt for JSON Web Tokens, and ldap-auth for LDAP integration. These plugins chain for multi-layer security, supporting DevOps automation for token validation and consumer management.

14. How does Kong support CI/CD integration?

Kong integrates with CI/CD via Admin API for config management, Terraform for IaC, and webhooks for event triggers. DB-less mode supports GitOps with YAML/JSON configs, enabling automated deployments in Jenkins, GitHub Actions, or ArgoCD for scalable API management.

15. What is Kong's declarative configuration?

Declarative configuration in DB-less mode uses YAML/JSON files to define services, routes, and plugins, stored in version control for GitOps. It supports dynamic reloading without downtime and integrates with Helm for Kubernetes, ideal for DevOps automation.

Discover how OpenShift enhances containerized API deployments.

16. Why use Kong for API security?

Kong secures APIs with plugins like mTLS, JWT, OAuth2, and rate-limiting, alongside ip-restriction and cors for access control. It supports WAF integration and real-time threat detection, making it a robust choice for DevOps-driven security in production.

17. How does Kong's traffic splitting work?

Kong's traffic splitting enables canary releases and A/B testing by routing traffic based on headers, weights, or paths. It integrates with Kong Mesh for advanced routing in microservices, supporting DevOps automation for real-time traffic management.

18. What is Kong's consumer management?

• Manages API consumers with RBAC.
• Supports key-based authentication.
• Integrates with IdPs for SSO.
• Provides real-time consumer metrics.
• Scales for enterprise consumers.
• Ensures compliance with access logs.
• Automates provisioning via Admin API.

19. When to use Kong's oauth2 plugin?

• For OAuth2 token validation in APIs.
• During SSO integration with IdPs.
• To secure third-party access.
• In DevOps for automated token management.
• For compliance with auth standards.
• During real-time token introspection.
• For chaining with other auth plugins.

20. How does Kong handle high availability?

Kong achieves high availability with distributed deployments, load balancing, and health checks. DB-less mode ensures stateless scaling, while Kong Mesh provides failover for microservices. DevOps teams use monitoring plugins like Vitals for real-time uptime tracking.

21. What is Kong's plugin chaining?

Plugin chaining allows multiple plugins (e.g., rate-limiting, JWT, logging) to execute in a defined order for complex workflows. Configurable via Admin API or Kong Manager, it supports DevOps automation for dynamic policy enforcement in API pipelines.

22. Why use Kong's Prometheus plugin?

The Prometheus plugin exports metrics like request latency and error rates to Prometheus, enabling DevOps teams to build Grafana dashboards for real-time monitoring. It supports SLO tracking and integrates with CI/CD for automated alerting.

Learn how GCP DevOps uses Prometheus for observability.

23. How does Kong's RBAC enhance enterprise security?

Kong's RBAC enforces fine-grained access control to Admin API and Kong Manager, supporting multi-team environments. It integrates with IdPs for SSO and enables DevOps automation for role assignment, ensuring compliance with security policies.

24. What is Kong's logging strategy?

Kong supports logging plugins like file-log, http-log, and syslog for request/response tracking. It integrates with external systems like ELK or Splunk for centralized logging, enabling DevOps teams to monitor and audit API activity in real time.

25. When to use Kong's ip-restriction plugin?

• For restricting API access by IP ranges.
• During geo-fencing for regional compliance.
• To block malicious traffic sources.
• In DevOps for automated access rules.
• For securing internal APIs.
• During real-time threat mitigation.
• For compliance with data residency laws.

26. How does Kong support multi-cloud deployments?

Kong supports multi-cloud with DB-less mode for stateless configs, Kubernetes integration for portability, and Kong Mesh for cross-cloud service mesh. DevOps teams use Terraform and Admin API to automate deployments across AWS, GCP, and Azure.

27. What is Kong's CORS plugin?

The CORS plugin manages cross-origin resource sharing, allowing or restricting API access from different domains. Configurable via Admin API, it supports DevOps automation for SPA and mobile app integrations, ensuring compliance with web standards.

28. Why use Kong for API transformation?

Kong's transformation plugins, like request-transformer and response-transformer, modify headers, bodies, or query parameters dynamically. They support use cases like API versioning, data masking, and payload normalization, integrated with DevOps for automated workflows.

29. How does Kong's Zipkin plugin work?

The Zipkin plugin enables distributed tracing by sending request traces to Zipkin, helping DevOps teams analyze API performance across microservices. It integrates with Kong Mesh for service mesh tracing, supporting real-time debugging.

Explore how GCP DevOps leverages tracing.

30. What is Kong's hybrid mode architecture?

Hybrid mode combines control plane (with database) and data plane (DB-less) nodes for flexibility. The control plane manages configs, while data planes handle traffic, enabling DevOps to scale and sync configurations in real time.

31. When to use Kong's key-auth plugin?

• For simple API key-based authentication.
• During consumer access control.
• To secure internal APIs.
• In DevOps for automated key rotation.
• For compliance with access policies.
• During lightweight auth setups.
• For chaining with other plugins.

32. How does Kong handle rate limiting in distributed systems?

Kong's rate limiting plugin uses Redis for distributed state management, ensuring consistent quotas across nodes. It supports fine-grained policies per consumer or route, integrating with DevOps for automated scaling and threshold updates.

33. What is Kong's service discovery mechanism?

Kong supports service discovery via DNS or integrations with tools like Consul or Kubernetes. Kong Mesh enhances discovery with Envoy-based service registry, enabling DevOps teams to automate dynamic routing in microservices architectures.

34. Why use Kong's request-transformer plugin?

The request-transformer plugin modifies incoming requests (headers, body, query) for tasks like API versioning, data enrichment, or payload formatting. It supports DevOps automation for dynamic transformations in CI/CD pipelines.

35. How does Kong's health check feature work?

Kong's health checks monitor upstream service availability, enabling failover and load balancing. Configurable via Admin API, they integrate with DevOps for automated scaling and ensure high availability in microservices environments.

36. What is Kong's role in API lifecycle management?

Kong manages the API lifecycle with tools for design (Kong Manager), deployment (Admin API, DB-less mode), security (plugins), and monitoring (Vitals, Prometheus). It supports DevOps for automated lifecycle workflows in CI/CD pipelines.

Learn how GCP DevOps manages API lifecycles.

37. When to use Kong's response-transformer plugin?

• For modifying API response headers or bodies.
• During data masking for compliance.
• To normalize response formats.
• In DevOps for automated transformations.
• For API versioning support.
• During real-time response customization.
• For chaining with other plugins.

38. How does Kong support API versioning?

Kong supports API versioning via route-based path prefixes or header-based routing, using plugins like request-transformer to rewrite URLs. DevOps teams automate versioning with Admin API or Terraform, ensuring backward compatibility.

39. What is Kong's bot detection capability?

Kong's bot-detection plugin identifies and blocks malicious bots using heuristics and custom rules. It integrates with rate-limiting and ip-restriction for layered protection, supporting DevOps automation for real-time threat mitigation.

40. Why use Kong's file-log plugin?

The file-log plugin logs request/response data to local files, useful for debugging and auditing. It supports DevOps integration with log aggregation tools like ELK, enabling centralized monitoring and compliance in production.

41. How does Kong's JWT plugin function?

The JWT plugin validates JSON Web Tokens, checking signatures and claims for secure API access. It supports advanced claims verification and integrates with DevOps for automated token management via Admin API.

42. What is Kong's upstream management?

Upstream management in Kong defines backend services with load balancing, health checks, and failover. Configurable via Admin API, it supports DevOps for automated scaling and ensures high availability in distributed systems.

43. When to use Kong's ACL plugin?

• For role-based consumer access control.
• During multi-tenant API management.
• To restrict access to specific routes.
• In DevOps for automated ACL updates.
• For compliance with access policies.
• During real-time permission changes.
• For chaining with auth plugins.

Explore how advanced GCP DevOps handles access control.

44. How does Kong's Konga UI assist DevOps?

Konga is an open-source GUI for Kong, enabling visual management of services, routes, and plugins. It simplifies configuration for DevOps teams, supports monitoring, and integrates with RBAC for secure multi-user access.

45. What is Kong's load balancing strategy?

Kong supports round-robin, weighted, and hash-based load balancing for upstream services. Health checks ensure failover, and DevOps teams use Admin API to automate balancing policies for high availability.

46. Why use Kong's http-log plugin?

The http-log plugin sends request/response logs to external HTTP endpoints, enabling integration with log aggregators like Splunk. It supports DevOps for centralized monitoring and real-time auditing in production.

47. How does Kong's canary release work?

Kong's canary release uses traffic splitting to route a percentage of requests to a new service version. Configurable via Admin API or Kong Mesh, it supports DevOps for automated rollouts and A/B testing.

48. What is Kong's service mesh architecture?

Kong Mesh uses Envoy as a sidecar proxy for microservices, providing mTLS, traffic splitting, and observability. It integrates with Kong Gateway for unified API management, enabling DevOps to automate service mesh deployments.

49. When to use Kong's syslog plugin?

• For logging to syslog servers.
• During centralized log management.
• To audit API activity.
• In DevOps for automated log integration.
• For compliance with logging standards.
• During real-time log streaming.
• For debugging production issues.

50. How does Kong handle API rate limiting?

Kong's rate limiting plugin enforces quotas per consumer, route, or globally, using Redis for distributed state. It supports dynamic thresholds via Admin API, enabling DevOps to automate rate policies for API protection.

Learn how scenario-based GCP DevOps manages rate limiting.

51. What is Kong's consumer groups feature?

Consumer groups in Kong manage sets of consumers with shared policies like rate limiting or ACLs. Configurable via Admin API, they support DevOps automation for scalable consumer management in enterprise environments.

52. Why use Kong's request-size-limiting plugin?

The request-size-limiting plugin restricts request payload sizes to prevent abuse, configurable per route or service. It integrates with DevOps pipelines for automated security policies, ensuring API stability.

53. How does Kong's LDAP plugin work?

The LDAP plugin authenticates consumers against an LDAP server, supporting enterprise SSO. Configurable via Admin API, it integrates with DevOps for automated auth workflows and compliance with identity standards.

54. What is Kong's proxy-cache plugin?

The proxy-cache plugin caches responses at the gateway, reducing backend load. Configurable with TTL and cache keys, it supports DevOps for automated cache management and performance optimization.

55. When to use Kong's correlation-id plugin?

• For adding unique IDs to requests.
• During distributed tracing.
• To debug request flows.
• In DevOps for automated tracing.
• For compliance with audit logs.
• During real-time monitoring.
• For integration with Zipkin.

56. How does Kong support API monitoring?

Kong supports monitoring via Vitals, Prometheus, and Zipkin plugins, providing metrics, traces, and logs. DevOps teams use Grafana dashboards and Admin API for real-time insights and automated alerting.

57. What is Kong's dynamic routing capability?

Kong's dynamic routing uses routes based on paths, headers, or methods, configurable via Admin API or Kong Manager. It supports DevOps automation for real-time routing updates in microservices environments.

Explore how GCP DevOps certification covers dynamic routing.

58. Why use Kong's response-ratelimiting plugin?

The response-ratelimiting plugin limits response rates to protect backend services, configurable per consumer or route. It supports DevOps automation for dynamic rate policies, ensuring backend stability.

59. How does Kong's upstream health checks work?

Upstream health checks monitor backend service health, enabling failover and load balancing. Configurable via Admin API, they integrate with DevOps for automated scaling and high availability.

60. What is Kong's API authentication strategy?

Kong supports multiple authentication strategies (JWT, OAuth2, key-auth, LDAP) via plugins, chaining for layered security. DevOps teams automate auth configs via Admin API, ensuring secure API access.

61. When to use Kong's request-termination plugin?

• For blocking malicious requests.
• During custom error responses.
• To enforce access policies.
• In DevOps for automated rules.
• For compliance with security standards.
• During real-time threat mitigation.
• For chaining with security plugins.

62. How does Kong's Konga UI enhance management?

Konga UI provides a visual interface for managing Kong configurations, supporting multi-user access with RBAC. It simplifies DevOps tasks like plugin setup and monitoring, reducing CLI dependency.

63. What is Kong's service versioning?

Kong supports service versioning via route-based path prefixes or header routing, using plugins like request-transformer. DevOps teams automate versioning with Admin API, ensuring backward compatibility.

64. Why use Kong's statsd plugin?

The statsd plugin sends metrics to StatsD-compatible systems, enabling DevOps teams to monitor API performance with tools like Grafana. It supports real-time analytics and automated alerting.

Learn how GCP DevOps uses StatsD for monitoring.

65. How does Kong's canary release strategy work?

Kong's canary release routes a subset of traffic to new service versions using traffic splitting. Configurable via Admin API or Kong Mesh, it supports DevOps for automated rollouts and testing.

66. What is Kong's API gateway clustering?

Kong clusters share configurations via a database or DB-less mode, ensuring consistency across nodes. DevOps teams use Admin API for automated cluster management, supporting high availability.

67. When to use Kong's bot-detection plugin?

• For identifying malicious bot traffic.
• During real-time threat mitigation.
• To protect API endpoints.
• In DevOps for automated bot rules.
• For compliance with security policies.
• During high-traffic events.
• For chaining with rate-limiting.

68. How does Kong's proxy-cache plugin optimize performance?

The proxy-cache plugin caches responses at the gateway, reducing backend load with configurable TTL and cache keys. DevOps teams automate cache policies via Admin API for performance.

69. What is Kong's consumer authentication?

Consumer authentication in Kong uses plugins like key-auth, JWT, or OAuth2 to validate consumer credentials. It supports RBAC and integrates with DevOps for automated consumer management.

70. Why use Kong's http-log plugin?

The http-log plugin sends logs to external HTTP endpoints, enabling integration with ELK or Splunk. DevOps teams use it for centralized logging, real-time auditing, and compliance.

71. How does Kong's service mesh enhance microservices?

Kong Mesh uses Envoy for Layer 7 traffic management, providing mTLS, traffic splitting, and observability. It integrates with Kong Gateway, enabling DevOps to automate microservices deployments.

Explore how real-time GCP DevOps leverages service mesh.

72. What is Kong's dynamic upstream routing?

Dynamic upstream routing in Kong routes requests to backend services based on headers or paths, configurable via Admin API. It supports DevOps automation for real-time routing updates.

73. When to use Kong's response-transformer plugin?

• For modifying response headers or bodies.
• During data masking for compliance.
• To normalize response formats.
• In DevOps for automated transformations.
• For API versioning support.
• During real-time customization.
• For chaining with other plugins.

74. How does Kong's Prometheus integration work?

Kong's Prometheus plugin exports metrics like latency and error rates to Prometheus, enabling DevOps teams to build Grafana dashboards for real-time monitoring and alerting.

75. What is Kong's RBAC configuration?

Kong's RBAC enforces access control to Admin API and Kong Manager, supporting multi-team environments. DevOps teams automate role assignments via Admin API, ensuring security compliance.

76. Why use Kong's syslog plugin?

The syslog plugin logs request/response data to syslog servers, enabling centralized log management. DevOps teams use it for real-time auditing and compliance in production.

77. How does Kong's health check ensure reliability?

Kong's health checks monitor upstream service health, enabling failover and load balancing. Configurable via Admin API, they support DevOps automation for high availability.

78. What is Kong's API transformation strategy?

Kong's transformation strategy uses plugins like request-transformer and response-transformer to modify headers, bodies, or query parameters. DevOps teams automate transformations for versioning and compliance.

Learn how GCP DevOps handles API transformations.

79. When to use Kong's correlation-id plugin?

• For adding unique IDs to requests.
• During distributed tracing.
• To debug request flows.
• In DevOps for automated tracing.
• For compliance with audit logs.
• During real-time monitoring.
• For integration with Zipkin.

80. How does Kong's consumer groups enhance management?

Consumer groups apply shared policies like rate limiting or ACLs to multiple consumers, configurable via Admin API. DevOps teams automate group management for scalable enterprise APIs.

81. What is Kong's proxy-cache strategy?

Kong's proxy-cache strategy caches responses at the gateway, reducing backend load with configurable TTL and cache keys. DevOps teams automate cache policies for performance optimization.

82. Why use Kong's request-size-limiting plugin?

The request-size-limiting plugin restricts payload sizes to prevent abuse, configurable per route or service. It supports DevOps automation for security policies, ensuring API stability.

83. How does Kong's LDAP plugin enhance security?

The LDAP plugin authenticates consumers against LDAP servers, supporting enterprise SSO. DevOps teams automate auth workflows via Admin API, ensuring compliance with identity standards.

84. What is Kong's canary release process?

Kong's canary release process routes a subset of traffic to new service versions using traffic splitting. DevOps teams automate rollouts via Admin API or Kong Mesh for testing.

85. When to use Kong's bot-detection plugin?

• For identifying malicious bot traffic.
• During real-time threat mitigation.
• To protect API endpoints.
• In DevOps for automated bot rules.
• For compliance with security policies.
• During high-traffic events.
• For chaining with rate-limiting.

Explore how GCP DevOps handles bot detection.

86. How does Kong's Konga UI support multi-user environments?

Konga UI supports multi-user environments with RBAC, enabling secure configuration of services, routes, and plugins. DevOps teams use it for visual management and monitoring.

87. What is Kong's service discovery strategy?

Kong's service discovery uses DNS or integrations with Consul or Kubernetes, enhanced by Kong Mesh for Envoy-based registry. DevOps teams automate dynamic routing for microservices.

88. Why use Kong's file-log plugin?

The file-log plugin logs request/response data to local files, supporting debugging and auditing. DevOps teams integrate it with log aggregators like ELK for centralized monitoring.

89. How does Kong's upstream management work?

Upstream management defines backend services with load balancing, health checks, and failover. DevOps teams automate configurations via Admin API, ensuring high availability.

90. What is Kong's API monitoring strategy?

Kong's monitoring strategy uses Vitals, Prometheus, and Zipkin plugins for metrics, traces, and logs. DevOps teams build Grafana dashboards for real-time insights and alerting.

91. When to use Kong's request-termination plugin?

• For blocking malicious requests.
• During custom error responses.
• To enforce access policies.
• In DevOps for automated rules.
• For compliance with security standards.
• During real-time threat mitigation.
• For chaining with security plugins.

92. How does Kong's dynamic routing enhance flexibility?

Dynamic routing routes requests based on paths, headers, or methods, configurable via Admin API. DevOps teams automate routing updates for flexible microservices management.

Learn how Azure DevOps enhances routing flexibility.

93. What is Kong's response-ratelimiting plugin?

The response-ratelimiting plugin limits response rates to protect backend services, configurable per consumer or route. DevOps teams automate policies for backend stability.

94. Why use Kong's statsd plugin?

The statsd plugin sends metrics to StatsD-compatible systems, enabling DevOps teams to monitor API performance with Grafana dashboards and automated alerting.

95. How does Kong's health check ensure reliability?

Health checks monitor upstream service health, enabling failover and load balancing. DevOps teams automate configurations via Admin API for high availability.

96. What is Kong's API transformation strategy?

Kong's transformation strategy uses plugins like request-transformer and response-transformer to modify headers, bodies, or query parameters. DevOps teams automate transformations for compliance.

97. When to use Kong's correlation-id plugin?

• For adding unique IDs to requests.
• During distributed tracing.
• To debug request flows.
• In DevOps for automated tracing.
• For compliance with audit logs.
• During real-time monitoring.
• For integration with Zipkin.

98. How does Kong's consumer groups enhance management?

Consumer groups apply shared policies to multiple consumers, configurable via Admin API. DevOps teams automate group management for scalable enterprise APIs.

99. Why use Kong's request-size-limiting plugin?

The request-size-limiting plugin restricts payload sizes to prevent abuse, configurable per route or service. DevOps teams automate security policies for API stability.

Explore how Azure DevOps FAQs address API security.

100. How does Kong's LDAP plugin enhance security?

The LDAP plugin authenticates consumers against LDAP servers, supporting enterprise SSO. DevOps teams automate auth workflows via Admin API, ensuring compliance with identity standards.

Learn how Azure DevOps integrates LDAP for authentication.